Mokume Gane and various pattern “Damascus” metals are examples of “forge-welding” wherein two different metals (or alloys) are heated to near-melting temperatures and then pressure is applied (usually with a hand-held hammer, power hammer, or hydraulic press) to weld the two metals into a single piece. The goal of pattern welding is fusing lots of different lamination layers of the original two metals, usually manipulated into interesting patterns.
These patterns are often enhanced with post-processing with abrasives and/or acid. “Damascus” usually involves steel with varying nickel or other add-ins which change how the metal etches under acid. Mokume Gane uses non-ferrous metals (gold, silver, copper, and various copper alloys).
@EthanWestern has successfully done both using the induction forge as a heat source at DMS. Cool stuff.
(Warning: simplification alert)
That being said, that’s not the welding class stuff being requested.
The “welding” discussed prior to this point deals more with using electricity to heat two metal pieces together and add a sacrificial third metal (usually also providing the electric current), to weld the two metals into a single piece. In this case, the weld-metal acts a little like glue and fills and strengthens the join, but the welding process fuses the two pieces together. There are several variants depending upon how the sacrificial metal is delivered, AC vs DC voltages, where the positive and negative terminals are attached, etc.
The goal of this kind of welding is the firm attachment of the two pieces of metal to each other. A pretty weld usually also means a well-executed, stronger weld, but the pattern of the weld is secondary to to the process.
We can do TIG, MIG, and stick welding at DMS using the welders on hand.
There is also oxy-acetylene welding (aka torch welding) which uses burning gas to heat the metals until they melt together (sometimes with more sacrificial metal added to strengthen the join). We don’t do oxy at the DMS due to storage restrictions for the gas needed.
Brazing and soldering are somewhat related, but only the added metal is melted, whereas the original parts are heated, but not melted. These processes can and have been done at DMS as well, but I don’t believe any special training is required before doing so here.